smog

noun

ˈsmäg 

ˈsmȯg

: a fog made heavier and darker by smoke and chemical fumes

also : a photochemical haze caused by the action of solar ultraviolet radiation on atmosphere polluted with hydrocarbons and oxides of nitrogen especially from automobile exhaust

smogless

ˈsmä-gləs 

ˈsmȯ-

adjective

Synonyms of smog

• haze
• fog
• cloud
• mist

Examples of smog in a Sentence

the city's smog was once so bad that darkness often prevailed, even at noon

Recent Examples on the Web

Rain can increase visibility when there’s smog, but its effect on air pollution is less certain, the weather service said. — Finnegan Belleau, Chicago Tribune, 19 July 2026

As Scientific American reported in 2023, wildfire smoke, smog and other toxic air have been linked to lower test scores in schoolchildren and higher rates of stress and depression. — Jackie Flynn Mogensen, Scientific American, 17 July 2026

In November 1966, New York City also experienced its most alarming smog on record. — Rebecca Florsheim, STAT, 17 July 2026

The types of turbines SpaceXAI used in Memphis can emit thousands of tons of smog-forming nitrogen oxides per year, according to manufacturers' spec sheets. — Lora Kolodny,jeniece Pettitt, CNBC, 16 July 2026

Word History

Etymology

smoke + fog

First Known Use

1880, in the meaning defined above

Phrases Containing smog

• anti-smog

Rhymes for smog

• blog
• bog
• clog
• cog
• dog
• flog
• fog
• frog
• grog
• hog
• jog
• log

Kids Definition

smog

noun

ˈsmäg 

also ˈsmȯg

: a thick haze caused by the action of sunlight on air polluted especially by smoke and automobile exhaust fumes

Etymology

from smoke and fog

Medical Definition

smog

noun

ˈsmäg also ˈsmȯg

: a fog made heavier and darker by smoke and chemical fumes

also : a photochemical haze caused by the action of solar ultraviolet radiation on atmosphere polluted with hydrocarbons and oxides of nitrogen especially from automobile exhaust